Door structure for recessed auto lift

ABSTRACT

A vehicle lift has a hydraulic cylinder and a U-shaped bolster, both of which are retracted in the floor when the lift is in the lowered position. A first door, positioned within the area defined by the bolster, rests on the floor when the bolster is in the lowered position and is picked up by the bolster when the vehicle is lifted. A second door is positioned about the ram below the bolster and rides on four pivoted arms. Springs connected to the arms supply force for raising the arms and the second door as the vehicle is raised. As the second door approaches the floor level, the arms pivot across vertical and are blocked from further pivotal movement in that direction so that they become rigid posts to support the second door at the floor level. Cams on the bolster operatively engage the arms as the bolster descends so as to pivot the arms back across the vertical position and allow them to descend as the bolster presses downwardly on the second door.

nited States Patent 1191 Clarke 1 51 Sept. 24, 1974 DOOR STRUCTURE FORRECESSED AUTO Primary Examiner-Richard A. Schacher LIFT AssistantExaminer-Jeffrey V. Nase [75] Inventor: Jesse E. Clarke, Hinsdale, Ill.Attorney Agent or Flrm Darbo Robertson &

Vandenburgh [73] Assignee: Autoquip Corporation, Chicago, Ill. [22]Filed: July 3, 1972 ABSTRACT [2]] Appl' 268,798 A vehicle lift has ahydraulic cylinder and a U-shaped bolster, both of which are retractedin the floor when Related Appllcatlon Data the lift is in the loweredposition. A first door, posi- [63] Continuation of Ser. No. 98,737, Dec.I6, 1970. tioned within the area defined by the bolster, rests on thefloor when the bolster is in the lowered position [52] US. Cl. 187/8.62,l87/8.6l and is picked up by the bolster when the vehicle is [5]] Int.Cl B66f 7/00 lifted. A second door is positioned about the ram [58]Field of Search l87/8.6l, 8.62 below the bolster and rides on fourpivoted arms. Springs connected to the arms supply force for raising thearms and the second door as the vehicle is raised. [56] References CitedAs the second door approaches the floor level, the

UNITED STATES PATENTS arms pivot across vertical and are blocked fromfur- 2 524 237 H1950 Smith I 187/8 62 ther pivotal movement in thatdirection so that they 2 577 378 12/1951 saint;;311iIIi""'"IIIIIIIIII187/832 4 become rigid Posts to Support the Second door at the 2:588:5l83/1952 Grushon l87/8.62 floor lfivel- Cams the bolster Operativelyengage the 2,655,224 10 1953 ou et 1 187/852 arms as the bolsterdescends so as to pivot the arms 2,732,917 1/1956 Hecker 187/8.62 backacross the vertical position and allow them to de- 2,961,069 11/1960Webster 187/8.62 scend as the bolster presses downwardly on the second3,393,772 7/1968 Pelouch g l87/8.62 x dom 3,608,675 /1971 Sherry 187/8627 Claims, 5 Drawing Figures PAIENIEnswzwu sum-1w Q INVENTOR. F I G. 3

JESSE E. CLARKE wmm i PAIENIEnSarzmn samurai FIG. 4

INVENTOR. JESSE E. CLARKE' 1 DOOR STRUCTURE FOR RECESSED AUTO LIFT Thisis a continuation of application Ser. No. 98,737 filed Dec. 16, 1970.

BACKGROUND AND SUMMARY OF THE INVENTION A desirable characteristic of avehicle lift is that it minimizes the obstruction of the bottom of thecar; thereby, a mechanic is given the maximum amount of freedom ofaccess to the bottom of the car to work on it. In the present invention,a U-shaped bolster is employed having a base with two upwardly extendingposts. A single hydraulic ram supports the bolster at the center of thebase. The vehicle engaging structure is supported on the upper ends ofthe posts. Preferably, this vehicle supporting structure is a pluralityof jointed arms.

It will be noted that if such a U-shaped bolster is to have anyappreciable depth (and thus provide significant clearance for workingspace) it is necessary that the bolster be recessed in the floor topermit the vehicle to be moved on or off the lift. This necessitates anopening in the floor. It is highly desirable that any such floor openinghave a door which will close the opening when the lift is retracted intothe floor and which will also close the opening when the lift andvehicle are raised. Without such a door, debris, tools, etc., will fallthrough the floor opening. Furthermore, with the lift in the raisedposition, there is a danger of a person stepping into the floor openingor tripping over it, with resulting injury. Also, in some servicingoperations performed on a vehicle, various objects are moved about thefloor under the car. These require floor support when moving across orstanding on the area occupied by the vehicle lift floor opening.Sometimes such objects have an appreciable weight and it is necessarythat the door be able to withstand significant loads. Another requisiteof such a door structure is that it be relatively simple, relativelyinexpensive and foolproof in operation. The principal object of thepresent invention is to provide a door structure that will solve thesevarious problems.

In the present invention, this is accomplished by using two doors, oneof which rests on the floor when the lift is recessed. As the bolsterrises out of the floor this first door is picked up by the base of thebolster and is thereby out of the way as much as is the base of thebolster. A second door below the bolster is raised into position by aplurality of pivoted arms which move across center so as to securelysupport the second door across the floor opening DESCRIPTION OF THEDRAWINGS FIG. 1 is a plan view of an embodiment of the inventron;

FIG. 2 is an elevational view of the lift as seen below floor level,with portions broken away, and with the lift in the retracted position;

FIG. 3 is a section taken at line 3-3 of FIG. 4;

FIG. 4 is a view corresponding to that of FIG. 2 with the bolster raisedabove the floor; and

FIG. 5 is a fragmentary view similar to FIG. 4 but showing the bolsterin the act of camming down the arms so that the lower door will descend.

DESCRIPTION OF SPECIFIC EMBODIMENT The following disclosure is offeredfor public dissemination in return for the grant of a patent. Althoughit is detailed to ensure adequacy and aid understanding, this is notintended to prejudice that purpose of a patent which is to cover eachnew inventive concept therein no matter how others may later disguise itby variations in form or additions or further improvements. The claimsat the end hereof are intended as the chief aid toward this purpose, asit is these that meet the requirement of pointing out the parts,improvements, or combinations in which the inventive concepts are found.

The lift of the present invention is powered by a ram 10 mounted in ahydraulic cylinder, not shown. Secured to the top of the ram is abolster, generally 11, comprising a base 12 and a pair of vertical posts13 and 14. Secured to the top of posts 13 and 14 is the vehicle engagingsuperstructure. Any such vehicle engaging superstructure could beemployed with the present invention, although I prefer to use jointedlinks, generally 15, as, for example, shown in my prior US. Pat. No.3,315,764. These are secured to plates 16 affixed to the tops of thebolster posts. There is a vertical rod 17 to prevent rotation of the ramand superstructure.

A frame, generally 19, forms a recess in the floor to receive thebolster l1 and defines an opening 20 at floor level. This frame includesa top plate 21, two side plates 22 and end walls 18. Above the base 12of the bolster is a first door 23. Door 23 is only slightly shorter thanthe distance between the two arms 13 and 14 of the bolster. It hasrecesses 24 so that the door fits about a pair of guides 25 secured tothe inner faces of the posts.

A second door 28 is positioned below bolster l1 and fits loosely aboutthe ram 10 and the anti-rotating rod 17 so that these are free to movevertically with respect to the second door. Door 28 rides on a pluralityof rollers 29 secured to the distal ends of levers or arms 30. Theproximal ends of arms 30 are welded to shafts 31 journaled in bearings32. There are four such arms secured to two shafts. The arms haveprojections 33. Springs 34 connect pins 35 on projections 33 and pins 36on frame 19.

With the ram and bolster in the retracted position, as illustrated inFIG. 2, the door 23 is resting on the top 21 of the frame and therebycloses that part of the opening 20 between the bolster posts. The door28 is held down against the tension of springs 34 by the bolster. As thebolster initially is raised from the lowered position, the lowered door28 follows the bolster up. When base 12 of the bolster reaches the upperdoor 23 it picks up the upper door and carries it out of the way, asillustrated in FIGS. 3 and 4. For all practical purposes, the upper door23 provides no more obstruction to the under side of the vehicle thandoes the bolster base 12. As the bolster moves above the floor opening,the arms 30 raise the lower door 28 to the floor level.

An important facet of the present invention is that the pivotal axes ofthe levers 30 are positioned so that the levers move across center" inthe final part of the range of movement. Thus, the shafts 31, whichdefine the pivotal axes, are positioned inwardly from end walls 18 whichserve as the final stop for the pivotal movement of the levers. When thelevers move across the vertical position and over against stops forminga part of end walls 18, any pressure on the floor 28 only presses thelevers that much harder against their stops so that the levers thenserve as rigid posts to support the door 28.

When the bolster 11 is to descend, the levers 30 must be moved backacross center (across the vertical position) so that they will permitthe descent of door 28. To achieve this, there are cams 37 on each endof the bolster. As best seen in FIGS. 3 and 5, these cams 37 descendthrough slots 38 in door 28 to contact arms 30. Only one such arm 30 ateach end need be contacted by a cam since the two arms at an end arepivotally tied together by shaft 31. The angular face of the cam pushesthe arms 30 back across center, as best illustrated in FIG. 5, so thatas the base 12 of the bolster comes into contact with lower door 28 itcan push the door down against the resistance of springs 34. Thus, thelift can retract from the FIG. 4 to the FIG. 2 position.

I claim:

1. In a vehicle lift apparatus of the type comprising a frame, a rampart and a bolster part recessed in a floor in a retracted position withsaid parts moving through a floor opening when moving from a retractedto a raised position, and a door to close at least a part of saidopening when the ram part is in the raised position, the improvementcomprising:

said door being a flat plate approximately the size of said opening and,when lowered, positioned horizontally about said ram pa'rt below thebolster part when the parts are in the recessed position and with theram part being free to move vertically through the door,

means mountd on the frame and operatively connected to the door forhorizontally raising the door behind the bolster part as the bolsterpart moves away from the retracted position until the door reaches thefloor opening and then for supporting the door at said opening, saidmeans comprising a plurality of levers having one end thereof pivotallyconnected to the frame below said opening and the other end bearingagainst said door, said levers being movable from a first position whensaid door is in a lowered position to a second position when the door isat said opening, means connecting said levers and frame and resilientlyurging said levers in a given direction from the first position towardthe second position, and fixed means separate from the levers andpositioned to contact the levers and block further movement of thelevers in said direction when said levers reach the second position.

2. In a vehicle lift apparatus of the type comprising a frame, a rampart and a bolster part recessed in a floor in a retracted position withsaid parts moving through a floor opening when moving from a retractedto a raised position, and a door to close at least a part of saidopening when the ram part is in the raised position, the improvementcomprising:

4 said door being a flat plate approximately the size of said openingand, when lowered, positioned horizontally about said ram part below thebolster part when the parts are in the recessed position and with theram part being free to move vertically through the door, means mountedon the frame and operatively connected to the door for horizontallyraising the door behind the bolster part as the bolster part moves awayfrom the retracted position until the door reaches the floor opening andthen for supporting the door at said opening, said means comprising aplurality of levers each having two ends, with one of said ends bearingagainst the door, a pivotal connection between the other end and theframe, each lever being movable between a first position at which thedoor is in the lowered position and a second position at which the dooris at floor level, said connection being so positioned that the leverpasses through and beyond a vertical position as the lever moves betweenthe first position and the second position, and a stop fixed to theframe and positioned to contact the lever after the lever reaches thesecond position and to prevent the lever from moving beyond the secondposition when moving in the direction of from said vertical position tosaid second position. 3. In an apparatus as set forth in claim 2,including means on one of said parts and positioned to operativelyengage said lever as the parts descend to move the lever from the secondposition toward and past said vertical position.

4. In an apparatus as set forth in claim 3, including a springconnecting said lever and said frame and resiliently urging said leverfrom said first to said second position, and wheel means on said one endof said lever to provide an antifriction contact with said door.

5. In an apparatus as set forth in claim 4, wherein the means to movethe lever is a cam extending downwardly from the bolster part.

6. In an apparatus as set forth in claim 5, wherein said bolster part isgenerally U-shaped with a base and two spaced posts extending upwardlyfrom the base and of a size such that all of the bolster except for thetops of the posts are below the floor opening when the parts are in theretracted position; and

including door means positioned between said posts and above said base.

7. In an apparatus as set forth in claim 6, wherein said door means hasa width greater than the width of the floor opening so that the doormeans will rest on the floor when the parts are retracted, and includingmeans operatively connecting the second door and the bolster part sothat the door means will remain on the bolster part when the parts areraised.

1. In a vehicle lift apparatus of the type comprising a frame, a rampart and a bolster part recessed in a floor in a retracted position withsaid parts moving through a floor opening when moving from a retractedto a raised position, and a door to close at least a part of saidopening when the ram part is in the raised position, the improvementcomprising: said door being a flat plate approximately the size of saidopening and, when lowered, positioned horizontally about said ram partbelow the bolster part when the parts are in the recessed position andwith the ram part being free to move vertically through the door, meansmountd on the frame and operatively connected to the door forhorizontally raising the door behind the bolster part as the bolsterpart moves away from the retracted position until the door reaches thefloor opening and then for supporting the door at said opening, saidmeans comprising a plurality of levers having one end thereof pivotallyconnected to the frame below said opening and the other end bearingagainst said door, said levers being movable from a first position whensaid door is in a lowered position to a second position when the door isat said opening, means connecting said levers and frame and resilientlyurging said levers in a given direction from the first position towardthe second position, and fixed means separate from the levers andpositioned to contact the levers and block further movement of thelevers in said direction when said levers reach the second position. 2.In a vehicle lift apparatus of the type comprising a frame, a ram partand a bolster part recessed in a floor in a retracted position with saidparts moving through a floor opening when moving from a retracted to araised position, and a door to close at least a part of said openingwhen the ram part is in the raised position, the improvement comprising:said door being a flat plate approximately the size of said opening and,when lowered, positioned horizontally about said ram part below thebolster part when the parts are in the recessed position and with theram part being free to move vertically through the door, means mountedon the frame and operatively connected to the door for horizontallyraising the door behind the bolster part as the bolster part moves awayfrom the retracted position until the door reaches the floor opening andthen for supporting the door at said opening, said means comprising aplurality of levers each having two ends, with one of said ends bearingagainst the door, a pivotal connection between the other end and theframe, each lever being movable between a first position at which thedoor is in the lowered position and a second position at which the dooris at floor level, said connection being so Positioned that the leverpasses through and beyond a vertical position as the lever moves betweenthe first position and the second position, and a stop fixed to theframe and positioned to contact the lever after the lever reaches thesecond position and to prevent the lever from moving beyond the secondposition when moving in the direction of from said vertical position tosaid second position.
 3. In an apparatus as set forth in claim 2,including means on one of said parts and positioned to operativelyengage said lever as the parts descend to move the lever from the secondposition toward and past said vertical position.
 4. In an apparatus asset forth in claim 3, including a spring connecting said lever and saidframe and resiliently urging said lever from said first to said secondposition, and wheel means on said one end of said lever to provide anantifriction contact with said door.
 5. In an apparatus as set forth inclaim 4, wherein the means to move the lever is a cam extendingdownwardly from the bolster part.
 6. In an apparatus as set forth inclaim 5, wherein said bolster part is generally U-shaped with a base andtwo spaced posts extending upwardly from the base and of a size suchthat all of the bolster except for the tops of the posts are below thefloor opening when the parts are in the retracted position; andincluding door means positioned between said posts and above said base.7. In an apparatus as set forth in claim 6, wherein said door means hasa width greater than the width of the floor opening so that the doormeans will rest on the floor when the parts are retracted, and includingmeans operatively connecting the second door and the bolster part sothat the door means will remain on the bolster part when the parts areraised.